1. Field of the Invention
The present invention generally relates to wheel rim constructions which permit a tire to undergo severe loading, or endure heavy duty conditions, and also permit the tire to run in a deflated state.
2. Background Information
Attempts have earlier been made, particularly in connection with cross-country vehicles, to design rim constructions which permit running with the tire under severe loading or heavy duty conditions, and also running with the tire in a deflated state, commonly referred to as run-flat driving. Examples of known constructions are given in SE-B-317,003, SE-B-362,219, DE-1,505,080, U.S. Pat. No. 2,028,601, U.S. Pat. No. 2,409,666, U.S. Pat. No. 4,151,870, U.S. Pat. No. 3,664,405, U.S. Pat. No. 3,669,174, U.S. Pat. No. 4,572,265 and SE-B-418,481 (=U.S. Pat. No. 4,016,917).
The construction disclosed in SE-B-418,481 relies on jaws or bead clamps which are elongate and which extend, when in their operative position, in the axial direction of the vehicle wheel to press the tire beads against the rim flanges. The bead clamps are retained in place by a clamping bolt passing through the rim bottom and mechanically pressing the bead clamps against the rim bottom, whereby to obtain a stable and strong engagement. These prior-art bead clamps have proved most useful and reliable for many types of vehicle tire.
It has however been found that these bead clamps may sometimes tend to rotate about the clamping bolt, particularly under heavy duty conditions and especially when using tires having a large axial width, particularly low-profile tires for forest machines and other cross-country vehicles. In fact, the purpose of the bead clamps is to mechanically fix the tire on the rim to prevent it from slipping thereon, also in the case of low air pressure. Another purpose of the bead clamps is to prevent air leakage between the tire beads and the rim flanges as a result of the tire beads coming loose from the rim flanges when the tire is subjected to high lateral stresses. If the bead clamps should rotate about the clamping bolt, the intended fixation of the tire would be undone.